Friction let-off for looms



March 24, 1925.

1,531,114 J. MCBRIDE FRICTION LEm-OFF FoR Looms Filed March 3l, 1923 2 Sheets-Sheet l J. MCBRIDE FRICTION LET-OFF FOR LOOMS Filed March 31, 1925 2 Sheets-Sheet 2 JOHN Mcmn.

ano? |1911 @UNITEDSTA-Tas Patented Mar. 24, 19,25.`

`mi'rENfrf oFF-ICE.

jl A.Torna MnRIDE, or 'CATASAQA PENNSYLVANIA.

| FRICTIoN LE'rforr ron` Looms.

Apbncation filed March 31, 1923. serial No. 629,035.

To all whom it may concern:v Be it Aknown that JOHN MCBRIDE, citizen of the United States, residing at Catasauqua,'in the county of Lehighand` State ofI "Pennsylvania, has invented. certainnew and usefuly `Improvements in Friction Let-offs for Looms, of `which the following, isl a specification.

employed what is known as ftheifriction let drawn off (the roll too rapidly, and to endeavor to keepy such threads :constantly under an even tension'between the warp kbeam and the woven silk. i

`-Various means yhave vbeen'used for this purpose, and among others there has been' olf. The.` common form of'this device embodies a drum at each end of the warp beam` around which is wound several coils A of exible strand, such'as'ropeor the l1ke,`

the ends of the .rope hanging vdown and being providedeach'with asuitable counterweight', keither directly attached tov the respective end or secured thereto through the medium of a lever. It isjnsual to take several wraps of the rope aroundlthe friction or brake drum, this being necessary in order to maintain the requisite tensionon the warp threads. y

Vith. the means above described, it is `found .in practice that the threads do not unwind from the drum smoothly and evenly because the rope tendsto grip tighter at some times than yat others on the drum. The result of this is that the weave is uneven, the number of picks per inch in part ofthe fabric varying from the number of picks per inch in other parts thereof. Furthermore, it is found that this means, is

defective because of the tendency to sudden" gripping which snaps thewarp threads and thus makes bad spots in the Weave, as well asl causing delay in theoperation of 'the loom. p' i The principal and most important object of the present invention isv to provide a novel arrangement of friction let off wherein the defectscaused bythe ordinary friction let off will lbe eliminated,`fand, by the use 'of which, a smooth and even fabric will be produced and breakage in the warp threads will be obviated.-

VWith theabove and other objects in view as will'behereinafter apparent, the inven-y tion consists in general of certain novel details of construction and combinations of parts hereinafter fully described, illustrated in the accompanying drawings and specifically claimed.

In the accompanyingdrawings, like char- Fig. 1 .is a view showing the warp beam of a b road silk loom with the improved letoff applied thereto. y

Fig. 2 is a section on the Figul. i

Fig. 3 is an enlarged detail of one end line 2--2 of of such a-v beam with a modifiedy arrange` Vmentof friction let-off.

Figure 4is Van enlarged detail showing the manner in .which the ropes are run over the pulleys. f y

In carrying 'out ythe objects of the present invention, there is provided theusual warp beam. 10, having journalled ends 11 supported in suitable bearings 12. It is tobe understood that these kbearings are carried bya framey 13 which is part of the frame of the loom, the remainder ofthe frame and loomy not being deemed necessary here to be shown, as the invention concerns itself only with the production of a novel friction 'brake means for the warp beam. At'each end of the warp beam, there is provided a friction drum 14, around which passes a. flexible strand which may be of any type of rope, either'n'ietallic or nonmetallic, may be leather or rawhide or a chain or the like. At one end of this strand is carried a counterweight 15 and, in the type shown in Figures 1 and 2, the strand passes up from the counterweight as at 16, and thence down as at 17 to a sheave 18 carried in a floor stand 19.

After passing in the sheave 18, the rope again passes up as at 20 over the top of the drum, and then down as atl 21 to pass under a second sheave 22. From this sheave the rope again passes over the drum 14, and has its remaining end brought down and connected to a lever 23 having one end pivoted to a floor stand 24, and carrying on its opposite end a counterweight 25 which may be adjustably engaged with any one of a acters of reference indicate like parts in the several vlews, and:

series of notches 26 formed on the upper side of the lever 23.

- It will be noted that the strand may be Wrapped entirelyv around the friction drum one or more times at any desired point. in its length.

ln the form shown in Fig. 3. the strand passes from the counterweight up and around the drum as at 2, and after Wrap.- ping around the drum once it extends upward as` at 28' to;l a sheave 29 supported above the drum on a bracket 8.0. The rope is then alternately passed beneath the drum and up and down the second' sheave 3.1 being finally brought down, Wrapped once around the drum` and thence led to. the lever 23 to, which it is secured as before.

Practice has shown that with this ar-. rangement a much more ideal braking of the warp bea-ni or roll may be effected, and by proper adjustment of: the counter* Weights7 the tension onl the iva-rp, threads may be regulated tothe desired degree,r and such tension Willlbe maintained throughout the weave operation Withoutperceptiblevariation. Thus the. sillr ivovenxvill be uni.- form in texture throughout its length, and will be free from` 'knotted warp. threads due to breakagel of such threads by uneven tension thereon.

It will be obvious that this must` be so when it; is; considered that the different portions of the exible strand which are in contact with the drun'i let are so` disposed it is desired to include all such as properly come Within the` scope claimed.

Having thus described the inventio1i,\vl1at isclaimed as new, is:

l. The combination with the Warp beam or roll of a loom; a brake drum carried by said roll, a'Sheave located in spaced relation to the brake drum, a flexible strand passing around the brake drum and sheave and being free from the drum between said drum and sheave, said strand beingk engaged on the drum only on the side remote from the sheave and means for exerting a tensile stress on said strand'.

The combination with a WarpA beam or roll ef a loom; of a brake drum carried by said warpl beam or roll, a plurality orf sheaves having their axis parallel. to, and spaced'from the axis of the drum, a. counter- Weight, a flexible strand having one end connected to said counterweiglat, said strand being passed around the drinn and the sheaves alternately, and means on `the remaining end' of the` strandl to exert pull against said counter'weiglit.

The combination with a Warp. beam or roll of a leoni; of a brake drum carried by said Warp beam or rold', a plurality of sheaves having their axis` parallel to and spaced fronrthe axis of the darum, aV coun.-

teryveiglit, a flexible strand having oneend connected te said' counteriveight, said strand being passed around the drinn Vand the sheaves alternately, means-on the remaining end of the strand to4 exert pull against said counterweight said means comprising a lever pivoted at one endand having the stand connected therete` intermediate its ends, and an adjustable counterWeig-ht slid-r -ably mounted on said lever.

In testimony- Whereat I- affix my. signature in presence of twa witnesses.

JOHN' MGBRIDE. Witnesses Timmer J; MeBnIDn,4 TANA SMLTH.. 

